DECENTRALIZED CONTROLS AND COMMUNICATIONS FOR AUTONOMOUS DISTRIBUTION NETWORKS IN SMART GRID

• US 20140249688A1
• Filed: 10/10/2012
• Published: 09/04/2014
• Est. Priority Date: 10/10/2012
• Status: Active Grant

• Current Assignee: New Jersey Institute of Technology
• Original Assignee: New Jersey Institute of Technology
• Inventors: Ansari, Nirwan, Lo, Chun-Hao
• Granted Patent: US 9,804,623 B2
• Time in Patent Office: Days
• US Class Current: 700/297
• CPC Class Codes: G05F 1/66 Regulating electric power
• CPC Class Codes: G06Q 10/04 Forecasting or optimisation specially adapted for administrative or management purposes, e.g. linear programming or "cutting stock problem" market predictions or forecasting for commercial activities G06Q30/0202
• CPC Class Codes: G06Q 50/06 Energy or water supply
• CPC Class Codes: H02J 13/00006 characterised by information or instructions transport means between the monitoring, controlling or managing units and monitored, controlled or operated power network element or electrical equipment
• CPC Class Codes: H02J 13/00019 using optical means
• CPC Class Codes: H02J 13/00024 by means of mobile telephony
• CPC Class Codes: H02J 13/00026 involving a local wireless network, e.g. Wi-Fi, ZigBee or Bluetooth
• CPC Class Codes: H02J 3/24 Arrangements for preventing or reducing oscillations of power in networks by control effected upon a single generator H02P9/00
• CPC Class Codes: H02J 3/381 Dispersed generators
• CPC Class Codes: H02J 3/46 Controlling of the sharing of output between the generators, converters, or transformers
• CPC Class Codes: Y02B 70/30 Systems integrating technologies related to power network operation and communication or information technologies for improving the carbon footprint of the management of residential or tertiary loads, i.e. smart grids as climate change mitigation technology in the buildings sector, including also the last stages of power distribution and the control, monitoring or operating management systems at local level
• CPC Class Codes: Y02B 70/3225 Demand response systems, e.g. load shedding, peak shaving
• CPC Class Codes: Y02B 90/20 Smart grids as enabling technology in buildings sector smart grids supporting the management or operation of end-user stationary applications in general, or like technologies with no associated climate change mitigation effect Y04S20/00
• CPC Class Codes: Y02E 40/70 Smart grids as climate change mitigation technology in the energy generation sector
• CPC Class Codes: Y04S 10/12 Monitoring or controlling equipment for energy generation units, e.g. distributed energy generation [DER] or load-side generation
• CPC Class Codes: Y04S 20/221 General power management systems
• CPC Class Codes: Y04S 20/222 Demand response systems, e.g. load shedding, peak shaving
• CPC Class Codes: Y04S 20/242 Home appliances
• CPC Class Codes: Y04S 40/12 characterised by data transport means between the monitoring, controlling or managing units and monitored, controlled or operated electrical equipment
• CPC Class Codes: Y04S 40/126 using wireless data transmission

Abstract

Technologies are generally described for addressing the bidirectional power flow conflict incurred by power surpluses produced from a number of households'"'"' on-location energy generation units (e.g., solar) in power distribution networks. A micro grid composed of households in a neighborhood may be considered as a generating- or consuming-resource entity at different time periods. The approach may be formulated as a power balance computation such that power balance may not be achieved within the micro grid itself, and therefore power sharing (or redispatching) among micro grids is operated, before requesting power from the macro grid, i.e., the fuel-based conventional grid. Enhancement of renewable energy utilization and reduction in the amount of data packet traffic in exchange of information and control messages via uplink and downlink transmissions throughout an overlay multi-tier communications network infrastructure may be taken into consideration in example implementations.

Claims

1. A method to facilitate decentralized controls and communications for autonomous distribution networks in a smart grid, the method comprising:

structuring at least a portion of the smart grid in a four tiered architecture, wherein

a first tier comprises a central control center (CCC) managing a plurality of Distribution Control Centers (DCCs) each DCC representing an Autonomous Distribution Network (ADN),

a second tier comprises a plurality of first Control Centers (CCs) each CC representing a subsystem,

a third tier comprises a plurality of second CCs each second CC representing neighborhood or a field area network, and

a fourth tier comprises a plurality of micro grids (MGs) each MG comprising one or more households and each MG being managed by a second CC in the third tier;

enabling exchange of power availability and/or need information among the households, the MGs, and the CCs through uplink and downlink communications;

abstracting aggregated data collected from one or more of multiple MGs, multiple substations, and/or multiple ADNs at each tier as the uplink and downlink communications are extended to higher tiers for transmission to a controller in a higher tier; and

enabling direct distribution of excess power among the MGs and subsystems.

2. The method according to claim 1, further comprising:

forming a connected, undirected tree graph based on the four tiered architecture, wherein each vertex of the tree graph represents a power distribution bus with associated households and each edge represents a line feeder with one of a power injection or a power extraction.

3. The method according to claim 2, further comprising:

designating a household a generating unit if P_vi>

0 and a consuming unit if P_vi<

0, wherein P_vi is a power value associated with a household v_i injecting or extracting power to or from the smart grid; and

designating the household as an idle unit when P_vi approaches about zero.

4. The method according to claim 2, further comprising:

determining a child-parent relationship (W) and a depth (D) for each node of the tree graph;

sorting the nodes of the graph tree in a descending order of the depth of each node; and

computing power flow values for each edge of the graph tree based on surplus or needed power of each node and W of each node.

5. The method according to claim 4, further comprising:

starting the computation from a leaf node with a largest depth value or a farthest node from a distribution transformer.

6. The method according to claim 1, further comprising:

if a power imbalance within an MG is balanceable by adjusting power flows among households of a same MG, limiting uplink and downlink communications to the third and fourth tiers as the power imbalance is corrected.

7. The method according to claim 6, further comprising:

if the power imbalance within the MG is not balanceable by adjusting power flows among households of the same MG, facilitating power sharing among two or more MGs by extending the uplink and downlink communications to the second tier as the power imbalance is corrected.

8. The method according to claim 7, further comprising:

if the power imbalance within the MG is not balanceable by power sharing among two or more MGs, facilitating power sharing among two or more substations by extending the uplink and downlink communications to the DCCs of the first tier as the power imbalance is corrected.

9. The method according to claim 8, further comprising:

if the power imbalance within the MG is not balanceable by power sharing among two or more substations, facilitating power sharing among two or more ADNs by extending the uplink and downlink communications to the CCC of the first tier as the power imbalance is corrected.

11. The method according to claim 1, wherein an amount of data to be transmitted to the controller in the higher tier is defined by an abstraction ratio at which information in an uplink transmission is reduced while power sharing among MGs, substations, and/or ADNs is performed.

12. The method according to claim 11, wherein the abstraction ratio is an amount of data that carries sufficient information to be transmitted to a higher tier divided by a total amount of data received from a lower tier.

10. (canceled)

13-17. -17. (canceled)

18. A smart power distribution network configured to facilitate decentralized controls and communications for autonomous distribution networks, the network comprising:

a first tier that comprises a central control center (CCC) managing a plurality of Distribution Control Centers (DCCs) each DCC representing an Autonomous Distribution Network (ADN);

a second tier that comprises a plurality of first Control Centers (CCs) each CC representing a subsystem;

a third tier that comprises a plurality of second CCs each second CC representing neighborhood or a field area network; and

a fourth tier that comprises a plurality of micro grids (MGs) each MG comprising one or more households and each MG being managed by a second CC in the third tier, wherein the network enables;

exchange of power availability and/or need information among the households, the MGs, and the CCs through uplink and downlink communications,

abstract aggregated data collected from one or more of multiple MGs, multiple substations, and/or multiple ADNs at each tier as the uplink and downlink communications are extended to higher tiers for transmission to a controller in a higher tier, and

direct distribution of excess power among the MGs and subsystems.

23. The network according to claim 18, wherein uplink and downlink communications are limited to the third and fourth tiers as a power imbalance is corrected if the power imbalance within an MG is balanceable by adjusting power flows among households of a same MG.

24. The network according to claim 23, wherein power sharing is facilitated among two or more:

MGs by extending the uplink and downlink communications to the second tier as the power imbalance is corrected if the power imbalance within the MG is not balanceable by adjusting power flows among households of the same MG;

substations by extending the uplink and downlink communications to the DCCs of the first tier as the power imbalance is corrected if the power imbalance within the MG is not balanceable by power sharing among two or more MGs; and

ADNs by extending the uplink and downlink communications to the CCC of the first tier as the power imbalance is corrected if the power imbalance within the MG is not balanceable by power sharing among two or more substations.

28. The network according to claim 18, wherein uplink and downlink communications are facilitated:

between the CCC and the DCCs via broadband communication networks;

between the DCCs and the CCs in the second tier via broadband cellular communication networks and fiber optic communication networks;

between the CCs in the second tier and the CCs in the third tier via cellular communication networks and wireless communication networks; and

between the CCs in the third tier and the MGs via wireless sensor networks (WSNs) employing one-hop or multi-hop transmissions.

29. The network according to claim 18, wherein each MG integrates local area networks (LANs) and home area networks (HANs).

19-22. -22. (canceled)

25-27. -27. (canceled)

30. A computer readable storage medium with instructions stored thereon for executing a method at one or more processors to facilitate decentralized controls and communications for autonomous distribution networks in a smart grid, the instructions comprising:

structuring at least a portion of the smart grid in a four tiered architecture, wherein

a first tier comprises a central control center (CCC) managing a plurality of Distribution Control Centers (DCCs) each DCC representing an Autonomous Distribution Network (ADN),

a second tier comprises a plurality of first Control Centers (CCs) each CC representing a subsystem,

a third tier comprises a plurality of second CCs each second CC representing neighborhood or a field area network, and

a fourth tier comprises a plurality of micro grids (MGs) each MG comprising one or more households and each MG being managed by a second CC in the third tier;

enabling exchange of power availability and/or need information among the households, MGs, and CCs through uplink and downlink communications;

abstracting aggregated data collected from one or more of multiple MGs, multiple substations, and/or multiple ADNs at each tier as the uplink and downlink communications are extended to higher tiers for transmission to a controller in a higher tier, wherein an amount of aggregated data to be transmitted to the controller in the higher tier is defined by an abstraction ratio at which information in an uplink transmission is reduced while power sharing among MGs, substations, and/or ADNs is performed; and

enabling direct distribution of excess power among MGs and subsystems.

31. The computer readable storage medium according to claim 30, wherein the instructions further comprise:

forming a connected, undirected tree graph based on the four tiered architecture, wherein each vertex of the tree graph represents a power distribution bus with associated households and each edge represents a line feeder with one of a power injection or a power extraction.

32. The computer readable storage medium according to claim 31, wherein the instructions further comprise:

designating a household a generating unit if P_vi>

0 and a consuming unit if P_vi<

0, wherein P_vi is a power value associated with a household v_i injecting or extracting power to or from the smart grid; and

designating the household as an idle unit when P_vi approaches about zero.

33. The computer readable storage medium according to claim 31, wherein the instructions further comprise:

determining a child-parent relationship (W) and a depth (D) for each node of the tree graph;

sorting the nodes of the graph tree in a descending order of the depth of each node; and

computing power flow values for each edge of the graph tree based on surplus or needed power of each node and W of each node.

34. The computer readable storage medium according to claim 33, wherein the instructions further comprise:

starting the computation from a leaf node with a largest depth value or a farthest node from a distribution transformer.

35. The computer readable storage medium according to claim 30, wherein the instructions further comprise:

if a power imbalance within an MG is balanceable by adjusting power flows among households of a same MG, limiting uplink and downlink communications to the third and fourth tiers as the power imbalance is corrected.

36. The computer readable storage medium according to claim 35, wherein the instructions further comprise:

if the power imbalance within the MG is not balanceable

by adjusting power flows among households of the same MG, facilitating power sharing among two or more MGs by extending the uplink and downlink communications to the second tier as the power imbalance is corrected;

by power sharing among two or more MGs, facilitating power sharing among two or more substations by extending the uplink and downlink communications to the DCCs of the first tier as the power imbalance is corrected; and

by power sharing among two or more substations, facilitating power sharing among two or more ADNs by extending the uplink and downlink communications to the CCC of the first tier as the power imbalance is corrected.

37-41. -41. (canceled)